Human Races

I think thought we can get an idea that a split, with only the level of selective pressures so far experienced, would take a lot of time.We have been separated (after "out of africa") for about 60,000 years. In that time the gentic differences between races is still smaller than that within a given "race". It may be that our use of technologies has enabled us to be less sensitive to the pretty different environments we inhabit. It may also just be a fluke that no mutation occured that prevented breeding between the different groups.

Around a million years?I thought there was some evidence that we went through a bottleneck of a small number of 1,000's of individuals a few 10,000's of years ago. Wouldn't that suggest that all "racial" differences are very recent?

Good point, I keep reading it as a snippet here and there but haven't seen anything backing it up. I'll try to find a source for you. I suppose I'm falling for it because it seems credible but there may in fact be several ways to measure this.This isn't it but is a useful addition to the discussion here:
Not FoundI think it is emphasizing the lack of usefulness of 'race'.Here is the statement repeated:
from: http://www.washington.edu/...useum/kman/the_idea_of_race.htm
"Human populations are not unambiguous, clearly demarcated, biologically distinct groups. Evidence from the analysis of genetics (e.g., DNA) indicates that there is greater variation within racial groups than between them. These facts render any attempt to establish lines of division among biological populations both arbitrary and subjective."
American Anthropological Association, 1998and from here: Page Not Found | Virginia State University "With the vast expansion of scientific knowledge in this century, however, it has become clear that human populations are not unambiguous, clearly demarcated, biologically distinct groups. Evidence from the analysis of genetics (e.g., DNA) indicates that most physical variation, about 94%, lies within so-called racial groups. Conventional geographic "racial" groupings differ from one another only in about 6% of their genes. This means that there is greater variation within "racial" groups than between them."However, none of these are pointing to an original source. That is suspicious. It is politically correct to support this view and then to see it repeated so often without proper orginal sources is odd. Maybe I didn't search hard enoughThere is a disucssion of issues where that seems to conclude that while race has some value it can't be over used either. There is a bit of correlation but that doesn't say anything about one individual
Penn Medical Ethics and Health Policy | Home[This message has been edited by NosyNed, 10-29-2003][This message has been edited by NosyNed, 10-29-2003]

Isn't the point that, if you use this definition, there are 1,000's (maybe 100,000's) of races? You could group people by any specific set of genetically determined traits. Hair colour, blood type, propensity for getting a specific cancer, tendancy to higho cholesterol and so on.Any narrow enough grouping can be useful in the medical arena but a grouping based on the external features we use to specify "race" isn't narrow enough to be useful on an individual basis.As an example:
A doctor may be faced with a specific indivdual in her/his office. There are some symptoms presenting. They need to expend money and time on some tests to narrow the probable cause down. They may know that an individual of a particular "race" has a greater chance of having specific genetic propensities. However, this may not be narrow enough to guide the tests in an effective way. More details about the individuals ancestors, blood relavtives may narrow the choices further. Some genetic testing may (and in the future will) narrow them effectively.The point being made here is that "race" is not very useful a tool to make judgements about any individual person.However, it may be that there is enough statisitcaly significance to "race" related propensities to make treating a population based on that ok. That is, an advertising campaign directed at a "race" to encourage them to modify eating habits or to be screened for certain conditions that might be somewhat more prevalent in that group than others.If that is true it is only temporarily useful bacause we don't have all the genetic information we would like.

I'm getting a bit lost in the details of this thread Peter. But if we are talking about races aren't we talking about 4 large divisions of humanity (or 3). Has the term "race" been redefined in this thread?If "race" means what it has historically meant then I think that it has been demonstrated to be a not useful or definitive categorization for any reasons (medical, cultural or whatever you pick). Do you think otherwise, Peter?

And isn't that where this whole thing started?If there is a new definition of the races of humans perhaps you could supply it? At least clearly enough so that we can tell how many there are.

Check this months issue of Scientific American.

I will confess to having given up following this thread awhile ago. However I thought a small article in the "American Scientist" might be interesting to the participants.This is from the Nov-Dec 2003 Issue:
"Black" and "White" Not Quite RightIt is a study of the genetics of Brazilians who are a mix of Portuguese and Africans. They grouped individuals into 'black', 'white' or 'intermediate' based on skin color.Some excerpts:
"In samples from both urban centers and rural districts, the distribution of African alleles was the same for the "black" and "intermediate" Brazilians: Both groups' average AA1 values fell between the European and African ends of the spectrum.and"The white Brazilians also showed a high proportion of African allelic markers, although the distribution was not as pronounced as in the black and intermediate groups. The reason for this became apparent when the identity of the markers was considered---the OCA2 gene, part of the test battery, encodes a protein that regulates pigment production, meaning that the marker itself contributed to the phenotype. When this site was excluded from the AA1 calculation, there were no significant differences in the African genomic ancestry of black and white study participants."Since I think we started off with a general idea of race, which to most people is associated with skin color other characteristics, I think this helps point out that race doesn't even guarentee a correlation with color.------------------
Common sense isn't

Perhaps the result is already there. I've seen one picture of "africans" that shows a very wide range of skin color. Maybe we started off with a limited connection between skin color and genetic makeup. The separation since then has allowed for more separation of the genetics.It all comes down to showing that the common or original idea of "race" doesn't mean what we thought it did.------------------
Common sense isn't